Gaseous luminous tubing circuit



Jan. 8, 1935. H, MENDELSQHN 1,986,939

Y' GASEOUS LUMINOUS TUBING CIRCUIT Filed septv, 1955 Jig. 27a- 15 .191 20h E00/ (23 A zo 13 19 1.9 @isf-1- Q zow x 22 I'/ ZZ laf 1?/ @man Mendelsohn 0c 20c Y Patented ,lan.,8, 1935 I I PAraN'T ortica l l A, 1,986,939

Gestions LUmNops mme cmcorr 'y anymnlneaael'sonn, Brooklyn, N. Y.

imputati@ september 7,1933, serial n1688503 iecinims. (otras- 124) This invention relates to electrical display devices and has special reference to discharge tubes and circuits therefor, the discharge tubes referred to being of the type wherein a suitable gas 8 such as Neon, and similar gases used in the art,

iills the tube andthe discharge takesplace between terminals through such gas.

In utilizing discharge tubes of this type, it is common to provide a step-up transformer so that 10 the ordinary, house current is stepped up .to about 15,000 volts the output of the secondary of the transformer amounting to about 30 milliamperes. Under the circuit conditions now employed, ithas been found impossible because of l5 uncontrolled ckering, to utilize more than about 45 feet of discharge tubing and it requires only about 1,5 milliamperes at 15,000 volts to properly energize such tubing. One cannot use, with the present circuit arrangement, a greater quantity of tubing although the output of the `transformer is, under the conditions stated, suiilcient for practically double the length of the tubing now used.

The reason for this condition isv well known in the art. For example, due to the characteristics of the discharge tube, such as high resistance before current flow startsand a much lower resistance as soon as currentilows, transformers with falling or so called poor characteristics are 80 used to preventihe destruction of the discharge tubing. Again, with such a transformer or anequivalent set-up such as a transformer with standard power characteristics and choke coil, usually in the primary of the transformer, a parallel circuit of two discharge tubes will not maintain a stable system of illumination, but icker at a rate dependingl upon complex factors existing in this circuit. Such factors may include the variable resistance of the tubes, the capacityl effects of the walls and electrodes, and the ignition and extinction voltages of the tubes.

Now it is one of the important objects of my invention, not to prevent flickering, but to promote, control, and maintain these flickerings, but

at 4such a rate that the object of the display shall be realized. For example, if a slow rate of ickering in the discharge tubes for the purpose of display is desired, a change in the frequency of the transformer supply is one of the various means to accomplish this object. On the other hand, if it is desired to maintain the rate of flickering such that the illumination appears steady and uninterrupted to the eye, that is, the iiickerings are so rapid that the time intervals between successive illuminations of a tube will,

be less than the time of ocular persistence of vision, then. the ordinary or house supply frequency applied to the input .terminals of the transformer used in the circuit described and mentioned below is suillcient for the usual dis- 5 play purposes, although higher frequences may be eised with the proper transformer, if so desir Although any transformer ofsuitable characteristics may be employedfit is another impor- 10'` tant object of my invention to use the so-called transformers with poor characteristics, commonly in use on practically allinstallations of display lighting using discharge tubing in series with the transformer secondary terminals, thus saving .expense and installation costs. Thisuse just referred to, would gainas its object the inclusion of practically double the amountl of discharge tubing in use at present in theroidinary installation, that is, from 45 feet discharge tubing to about feet of such luminous discharge tubing, all energized from a single transformer.

A further important object of the invention is the use of a rectifier of either the full or halfwave type employing thermionic or cold cathodes, in combination with a set of discharge tubes so that a controlled flickering results from the circuit arrangement.

Another important object of the invention is to provide a pair of discharge tubes and a circuit therefor which will include a thermionic rectifier constituting a rapidly acting switch by the use of which current is intermittently passed through one tube and at the expense of the other, that is with current flow in one tube, current flow 35 either stops or falls in the other, depending on the tube 'chosen as reference, and to accomplish the object of controlling the flickering.

Still another object is to operate more than one setof tubes, on a transformer secondary, so that the full output of this secondary may be secured, the discharge tubes used being of any desired length and currentrequirements consistent with the circuit invention and combination described below.' These discharge tubes may further'have 5 any inductive or static characteristicsincident ,u to their manufacture and within the limitations of the circuit mentioned. Y

Another most important object is to prevent dangerous rises of voltage across the apparatus 50 used in this circuit including `tubing, rectifier, and transformer terminals at secondary.

With the above and other objects in view, as willbe presently set forth, the invention consists in general of certain novel details of constructionl and combinations of parts hereinafter fully dedescribed, illustrated in the accompanying drawing and specifically claimed. y

In the accompanying drawing, like characters of reference indicate like parts in the several views, and:-

Figure 1 is a typical wiring diagram disclosing the invention.

Figure 2 is a diagrammatic showing of a modilied form of interrupter for use herewith.

Figure 3 is a view similar to Figure 2 but showing a second modification of the interrupter.

Figure 4 is a View similar to Figure 2 but showing a third modification of the interrupter.

As shown in Figure l, there is provided a pair of line wires 10 and 11 receiving current from any suitable source of alternating current. These wires are connected to the terminals of the primary winding 12 of a transformer having a secondary winding 13. The transformer is of the step-up type and is constructed in such manner that the output from the secondary winding will be at a voltage of substantially 'T500-15,000 volts. At 14 to 15 are shown two discharge or glow tubes. As here represented merely straight tubes are shown, but it is obvious that these tubes are tobe bent, as is common in such signs, to the configuration to be displayed. The terminals of the tube 14 are connected by conductive connections 16 to' the terminals of the secondary winding 13 and it is to be particularly noted that tube 14 is of higher resistance than tube 15. One terminal of the tube 15 is connected to the corresponding terminal of the tube 14 by a conductive connection 17. At 18 is a thermionic rectifier although a cold cathode type of rectifier may alsov be used at this point in the circuit. The thermionic rectier or cold cathode type of rectigermay be of the half-wave or full wave type so connected as to perform the function shown in the diagram.

4 Using the thermionic rectifier for illustrative purposes, 18, the thermionic rectifier has plates 19 and laments 20, the latter being heated from a suitable source of current here indicated for convenience by the battery 21. Between the remaining terminal of the tube 14 and the filaments 20 is a conductive connection 22. The plates 19 are connected to the remaining terminal of the tube 15 by a conductive connection 23.

Under these conditions, the alternating current from the secondary will pass alternately through the tube 14 and intermittently through the tube 15 because of the presence of the rectifier 18. This will produce a luminous flickering in each tube and with a speed depending upon the circuit arrangements. To understand that this is so, it may be assumed that there is a direct connection, eliminating the rectifier 18 between the tubes 14 and 15 at each terminal. Then, because of the greater resistance of the tube 14 only the tube 15 will glow.

However, when the rectifier 18 is interposed current to the tube 15 is intermittently interrupted. The current being interrupted in tube 15, permits tube 14 to glow. When the rectifier 18 permits current to flow through 15, tube 15 being of lower resistance glows and tube 14 has its glow extinguished. If, however, the interruptions of the rectifier are made of very short duration, if so desired, and due to the transformer supply frequency, the tubes may be made to appear to glow continuously. In other words, the time intervals during which the current is interrupted in l5 and the resulting rate'of flickering in tubes 15 and 14 respectively may be made ilillr 3.19m;

or less than the persistance of ocular vision according to the needs of the display installation.

It will be observed that while the diagram here disclosed appears to represent the tubes 14 and 15 as connected in parallel, yet the effect is entirely different from the usual parallel connection of a pair of tubes since at one instant the current is completely shut oft' from tube 15, and

all of it iiows through tube 14 causing 14 to become luminous, then in the next instant current flows through tube 15 and it becomes luminous, while tube 14 becomes non luminous for an instant, and this cycle continues as long as the display is in operation.

Obviously, the circuit for the tube 15 may run directly from the secondary terminals and it is also obvious that the transformer may be of either the closed or open core type, and may if desired, have a choke coil associated therewith without affecting the principles involved in the invention itself.

In the form of the invention shown in Figure 2, the wiring connections are the same as in Figure 1 but the interrupter 18a has but a single plate 19a and a single filament 20a, the device thus being a half-wave interrupter.

In Figure 3 the interrupter 18h has an anode 19h and a cold cathode 20h, and the device forms a cold cathode, half-wave interrupter.

In Figure 4 the interrupter 18e has a pair of anodes 19e with a pair of cold cathodes 20c arranged on opposite sides of the anodes, and forms a cold cathode, full wave interrupter.

It is obvious that changes may be made in the form and construction of the invention without departing from the material principles involved so that it is to be understood that all forms covered by the appended claims are claimed as the invention.

-What is claimed, ist- 1. The combination with a pair of discharge tubes and parallel circuit connections therefor including a transformer secondary, the circuit though one of said tubes being of less resistance than the circuit through the second of said tubes, and a thermionic rectifier in the circuit of less resistance.

2. The combination with a pair of discharge tubesand parallel circuit connections therefor including a transformer secondary, the circuit through one of said tubes being of less resistance than the circuit through the second of said tubes and a cold cathode type of rectifier in the circuit of less resistance.

3. The combination with a pair of discharge tubes, one of which is of greater electrical resistance than the other, a transformer including a secondary, conductive connections between the terminals of the secondary and the terminals of the relatively high resistance tube, a conductive connection between one terminal of the relatively high resistance tube and the corresponding terminal of the relatively low resistance tube, and aconnection between the remaining terminals of said tubes including a thermionic rectifier.

4. The combination with a pair of discharge tubes, one'of which is of greater electrical resistance than the other, a transformer including a secondary, conductive connections between the terminals of the secondary and the terminals of the relatively high resistance tube, a conductive connection between one terminal of the relatively high resistance tube and the corresponding terminal of the relatively low resistance tube, and a connection between the remaining terminals of tu l said tubes including a' cold cathode type of rectifier.

5. The combination with a pair of discharge tubes including a rst tube of higher resistance than the second tube, a transformer secondary, a circuit for the first tube comprising whollyconductive connections between the terminals of the transformer secondary and the first tube, and a circuit for the second tube including vconnections between the terminals of the vtransformer' secondary and second tube, one of which has a thermionic rectifier interposedtherein.

6. 'I'he combination With` afpai'r of discharge tubes including a first tube of higher resistance than the second tube, a transformer secondary,

a circuit for the rst tube comprising wholly conductive connections between the terminalsof the transformer secondary and the first tube, and a circuit for the second tube including connections between the terminals of the transformer secondary and second tube one of which has a cold cathode type of rectifier interposed therein.

'1. The combination with a pair of discharge tubes and parallel circuit connections therefor including a transformer secondary, the circuit through one of said tubes being of less resistance than the circuit through the second of said tubes, and a full-wave thermionic rectifier in the circuit of less resistance.

8. The combination with a pair of discharge tubes and parallel circuit connections therefor including a transformer secondary, the circuit through one of said tubes being of less resistance than the circuit through the second of said tubes, and a full-wave cold cathodetype of rectierin the circuit of less resistance. .n

9. The combination with a pair of vdiscl'farge tubes, one of which is of greater electrical g-re`- sistance than the other,`a transformer including Aa secondary, conductive'connections between the terminals of the secondary and the terminals of the relatively high resistance tube, a conductive connection between one terminal of the relatively high resistance tube and the corresponding terminal of the relatively low resistance tube, and a connection between the remaining terminals of saidl tubes including a full-wave thermionic rectifier.

10. 'I'he combination with a pair of discharge tubes, one of which is of greater electrical resistance than the other, a transformer including a secondary, conductive connections between the terminals of the secondary and the terminals of the relatively high resistance tube, a conductive connection between one terminal of the relativelyhigh resistance tube and the corresponding terminal of the relatively low resistance tube, and a connection between the 'remaining terminals of said tubes including a full-wave cold cathode rectier.

11. The combination with a pair of discharge tubes including a rst tube of higher resistance than the second tube, a transformer secondary, a circuit for the rst tube comprising wholly conductive connections between the terminals of the transformer secondary and the first tube, and a circuit for the second tube includingconnections between the terminals of the transformer secondary and second tube, one of which has a full-wave thermionic rectifier interposed therein. v

12. The combination with a pair of discharge tubes including a xfirst tube of higher resistance thanv the second tube, a transformer secondary, a circuit'for the rst tube comprising wholly conductive connections between the terminals of the transformer secondary.` and the first tube, and a circuit for the second tube including connections between the terminals of the transformer secondary and second tube, one of which has a full-'wave cold cathode rectifier interposed therein, 1

13. The combination with a pair of discharge;

'tubes and parallel circuit connections therefor,

and a thermionic interrupter of the half-wave rectifying type in the circuit of less resistance.

14. The combination with a pair of discharge tubes and parallel circuit connections therefor, including a transformer secondary, the circuit through one of said tubes being of less resistance than the circuit through the second of said tubes, and a therrnionic interrupter of the full-wave rectifying type in the circuit of less resistance.

15. The combination with a pair of discharge tubes and parallel circuit connections therefor, including a transformer secondary, the circuit through one of said tubes being of less resistance than the circuit through the second of said tubes, and a cold cathode interrupter of the half-wave rectifyingtype in the circuit of less resistance.

16. The combination with a pair of discharge tubes and parallel circuit connections therefor, including a transformer secondary, the circuit through one of said tubes beingof less resistance than the circuit through the second of said tubes, and a cold cathode interrupter of the full-wave rectifying type in the circuit of less resistance. 

